I stand to be corrected here but from my hazy memory I seem to recall that one of the reasons airstairs were de-activated and then subsequently removed from the A320 was not due to their steepness and complexity, but that the fairing door microswitches were not up to the job and were giving "DOOR OPEN" ECAM messages in flight.
I can never recall the airstairs being used and as a result of in service problems the control CB's were permanently pulled and collared.
The airlines ordering the A320 at the time (I'm going back to 1988/89 here) had little need for airstairs and coupled with the natural concerns the crews had with the in flight indications, they were rapidly done away with.